Introduce a layering in the invalidation component as public and impl

components/invalidation/impl/unacked_invalidation_set.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef COMPONENTS_INVALIDATION_UNACKED_INVALIDATION_SET_H_
-#define COMPONENTS_INVALIDATION_UNACKED_INVALIDATION_SET_H_
+#ifndef COMPONENTS_INVALIDATION_IMPL_UNACKED_INVALIDATION_SET_H_
+#define COMPONENTS_INVALIDATION_IMPL_UNACKED_INVALIDATION_SET_H_
 
 #include <set>
 
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
-#include "components/invalidation/invalidation.h"
-#include "components/invalidation/invalidation_export.h"
-#include "components/invalidation/invalidation_util.h"
+#include "components/invalidation/public/invalidation.h"
+#include "components/invalidation/public/invalidation_export.h"
+#include "components/invalidation/public/invalidation_util.h"
 
 namespace base {
 class DictionaryValue;
 }  // namespace base
 
 namespace syncer {
 
 namespace test_util {
 class UnackedInvalidationSetEqMatcher;
 }  // test_util
@@ skipping 86 matching lines @@
   invalidation::ObjectId object_id_;
   InvalidationsSet invalidations_;
 };
 
 typedef std::map<invalidation::ObjectId,
                  UnackedInvalidationSet,
                  ObjectIdLessThan> UnackedInvalidationsMap;
 
 }  // namespace syncer
 
-#endif  // COMPONENTS_INVALIDATION_UNACKED_INVALIDATION_SET_H_
+#endif  // COMPONENTS_INVALIDATION_IMPL_UNACKED_INVALIDATION_SET_H_